Railway traffic control systems



Sept. 9, 1958 c. F. D. VENNING ET AL 2,851,590

RAILWAY TRAFFIC CONTROL SYSTEMS Filed Mdrch 4. 1953 7 Sheets-Sheet 1 m 1 2 HT wmmm um HEN wwkw m N N M N ML Sept. 9, 1958 C. F. D. VENNING ET AL RAILWAY TRAFFIC CONTROL SYSTEMS 7 Sheets-Sheet 2 Filed March 4. 1953 NE N$ MNEN Eb NBMQ M p 1958 c. F. D. VENNING ET AL 2,851,590

RAILWAY TRAFFIC CONTROL SYSTEMS Filed March 4. 1953 7 Sheets-Sheet 3 .I'IWIJI MNMR NE MR; Eb TW H N N 4 U SE mam v5: m v ELM N a S F .33 ms:

' Sept. 9, 1958 Filed March 4. 1953 C.- F. D. VENNING ET AL RAILWAY TRAFFIC CONTROL. SYSTEMS 7 Sheets-Sheet 4 Sept. 9, 1958 c. F. D. VENNING ET AL 9 RAILWAY TRAFFIC CONTROL SYSTEMS Filed March 4. 1955 '1 Sheets-She'et 5 Sept. 9, 1958 c. F. D. VENNING ET AL 2,851,590

RAILWAY TRAFFIC CONTROL SYSTEMS Filed March 4. 1953 7 Sheets-Sheet '7 my la. my). my 16.

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INVENTORS: filzapies llamas Dwkson Venzzm THEIR A WTOBMFY United States Patent RAILWAY TRAFFIC CONTROL SYSTEMS Charles Francis Dickson Warming and John Sydney Hawkers, London, England, assignors to Westinghouse Brake and Signal'Cornpany, Limited, London, England This invention relates to railway trafiic control systems for sections of track comprising a number of alternative routes, the various track switches and signals involved in each of which are arranged to be controlled by the combined actuation of control elements such as circuit controllers associated with. the entrance and exit ends of the route and usually arranged upon or associated with a track diagram at a point of control.

The control system of the invention comprises identical circuit controllers, preferably of the push button type, associated with the ends of each route, the setting up of a route for trailic in one direction or the other being dependent upon the order in which the two circuit controllers at the route. ends are. actuated.

A system of this type is described in the specification of British Patent No. 499,340 granted January 23, 1939, to Westinghouse Brake and Signal Company, Limited, which corresponds to United States Patent No. 2,244,401, granted to John M. Pelikan, and the present invention has for its object to provide an improved control system of the same general character.

According to the principal feature of the invention, the actuation of a circuit controller at the entrance end of the desired route is arranged to efiect the energization of a corresponding relay (hereinafter termed a setup relay), which, when thus energized, diverts the circuits of all other circuit controllers to cause any one of these circuit controllers, when actuated, to effect the energization of another corresponding relay (hereinafter termed a destination relay) instead of the set-up relay of this circuit controller, this destination relay, when ener ized, cooperating with the set-up relay previously energized to eifect the energization of a route relay for the route corresponding to the two circuit controllers.

Preferably the energization of a set-up relay is arto effect the energization of a relay (hereinafter termed a conditioning relay) common to all the set-up relays. This conditioning relay, when energized, diverts the circuit controlled by: a circuit controller subsequently actuated to cause the destination relay of this circuit ozntroller to be energized.

in other Words, the actuation of a circuit controller effects the energization of its set-up relay unless the conditioning relay is energized, in which case the circuit controller, when actuated, effects the energization of its destination relay instead of its set-up relay.

In carrying the invention into practice, certain interlocking and proving arrangements are provided so as to facilitate operation.

For example, the circuit controllers at ends of route are electrically interlocked with one another so that only one circuit controller can be effective at a time.

The circuit through which each set-up relay is energized contains a back contact of the conditioning relay, which insures that other set-up relays must be deenergized before said set-up relay can be energized.

The circuit through which each destination relay is energized contains a back Contact of the set-up relay 2 controlled by the same circuit controller, and preferably also a front contact on a repeaterv relay energized by the actuation of the corresponding circuit controller. These circuits alsocontain a front contact of the conditioning relay.

Preferably, the energization ofeach set-up relay is arranged to be controlled by. an aforementioned repeater relay energized by the actuation of the corresponding circuit controller, the energizing circuit of the set-up relay including a front contact of, the. repeater relay and a back contact of the destination relay for this circuit controller.

Since it is arranged. that only one circuit. controller can be effectively operated at attime, in order to prevent an attempt being made. to cause simultaneous setting of conflicting routes, each set-up relay, when energized, 1

completes a holding circuit for itself, so that the circuit controller at the entrance end of the route controlling the said set-up relay can bereleased to normal so as to permit the actuation of another circuit controller at the exit end of the route to energize a destination relay. The said holding circuit includes a front contact of the set-up relay itself and a back contact of a relay which repeats the energization of any destination relay. This holding circuit is transferred to include a front contact of the destination relay when this is energized; The energization of a set-up and a destination relay effects operation of the corresponding route relay.

The release of the destination circuit controller deenergizes its destination relay which in turn interrupts the holding circuit of the set-up relay. The, destination repeater relay, having a slow release feature, prevents its back contacts closing for such a period asv to permit the deenergization of the set-up relay.

In order to cancel an initial set-up condition before a destination relay is energized, the holding circuit for an. energized set-up relay may be broken by operating a cancel key having a normally closed contact included. in the holding circuit of the set-up relay. Alternatively, this cancellation maybe effected by operating the set-up circuit controller to a second operative position, which would be arranged to interrupt the holding circuit, instead of a separate cancel button.

In order to restore aroute relay to normal or to cancel a route already set up, this second operative position is utilized, thereby deenergizing the signal control relay of the signal at the route entrance and, when conditions permit, normalizing the route relay. In addition, the route relays may be made self-normalizing, this be.- ing governed by the actual passage of a train or vehicle through the route.

Illuminated indication devices are preferably provided adjacent to each circuit controller, the operating circuits of these devices beingso controlled that, when a set-up relay is energized, a flashing indication is given by the corresponding indication device, whereas, when the route relay is energized, this indication is changed to a steady illumination of the device, the indication device at the exit end of the route becoming at the same, time steadily illuminated to indicate that the destination circuit controller may be released.

Arrangements are provided for preventing the energization of a route relay in the event of any part of the route being in conflict with another established route.

The interlocking and proving arrangements above described may be supplemented by other safety arrangements, the connections and relay arrangements for interlocking and proving the operation of the system being obvious to those skilled in the art.

The indication displayed by the various signals required for traffic along a route established as above described may be effected in any suitable and well-known manner.

2,851,59O r i M The accompanying drawings, Figs. la, 1b, 1c, 1d, 16, and 1 when placed in relation to each other as shown in the diagram in Fig. 2, constitute a diagrammatic view showing one form of apparatus embodying our invention, in which:

Fig. la illustrates a track model and control panel embodying push button circuit controllers designated by the reference characters APB, BPB, CPB, and DPB, light indication devices designated by the reference characters AKE, BKE, CKE, and DKE, and a cancel button. Also shown in Fig. 1a are push button repeater relays designated by the reference characters APBR, BPBR, CPBR, and DPBR, and the control circuits for these relays.

Fig. 1b shows lamps A(H)KE and A(B)KE for indication device AKE, lamps B(H)KE and B(B)KE for indication device BKE, lamps C(H)KE and C(B)KE for indication device CKE, and lamps D(H)KE and D(B)KE for indication device DKE. Route relays, designated by the reference characters ABLR, CBLR, CDLR, BALR, BCLR and DCLR, are also shown in Fig. 1b.

Fig. lc shows approach locking relays designated by the reference characters ABLS, BALS, CDLS, and DCLS, time element relays designated by the reference characterters ATH, BTI-I, CTH, and DTH, timing stick relays designated by the reference characters AIS, BJS, CIS, and

DJS, and track stick relays designated by the reference characters UTS, YTS, WTS, and ZTS.

'Fig. 1d shows set-up relays designated by the reference characters ASR, BSR, CSR, and DSR, destination relays designated by the reference characters ADR, BDR, CDR, and DDR, a conditioning relay designated by the reference character CR, a destination repeater relay designated by the reference character DRP, a flasher relay designated by the reference character FR, and an alter-- nator designated by the reference character L.

Fig. 1e shows normalizing relays designated by thereference characters ANR, BNR, CNR, and DNR.

Fig. 1f shows a track and signal layout embodying crossover track switches designated by the reference characters A1 and B1, and signals designated by the referencecharacters SA, SB, SC, and SD, at locations a, b, c, and d, respectively. Operating mechanisms for switches A1 and B1 are designated by the reference characters AIM and BlM, respectively, and are controlled by a polar switch control relay designated by the reference character IWLR. Operating mechanisms for signals SA, SB, SC, and SD are designated by the reference characters. AHG, BHG, CHG, and DHG, respectively, and are controlled by signal relays designated by the reference char acters AHR, BHR, CHR, and DHR, respectively. Track relays are designated by the reference character R preceded by the reference character for the corresponding track section.

Fig. 2 shows the arrangement of Figs. 1a to If, in-

clusive, in relation to each other, for showing a form of apparatus embodying our invention.

The contacts of track relays are shown apart from the symbols for the relays by which they are operated. Each such contact, in circuits which are traced in the specification, is designated by a number, placed adjacent the contact, in conjunction with the reference character for the relay, by which it is operated, placed above the contact. Track relay contacts in circuits which are not traced in the specification are designated only by the reference character for the relay, by which they are operated, placed above the contact.

The lighting circuits for the indication lamps can be supplied with alternating current from a suitable source such, for example, as an alternator shown in Fig. 1d, designated by the reference character L, which has terminals designated by the reference characters BX and NX.

The control and operating circuits for other devices shown in the accompanying drawings can be energized by current from any suitable source such, for example, as a battery shown in Fig. 1f, designated by the reference is pulled out.

4 character Q, which has positive and negative terminals designated by the reference characters B and N, respectively.

In the description, the various expressions have the following well-known meanings:

A relay is said to pick up when its operating coil is energized and the relay armature assumes its energized position. This is also referred to as the relay becoming energized.

A relay is said to release or to drop away when its operating coil becomes deenergized and its armature assumes its deenergized position.

A relay front contact is a contact which closes when the relay picks up, and a relay back contact is a contact which is closed when the relay is released.

The term setting up a route is intended to comprise the correct positioning of any switches over which the route lies, and the clearing of a signal governing the entry of trafiic onto the route.

Referring further to the drawings, in Fig. la, push button circuit controllers APB, BPB, CPB, and DPB, are mounted at points a, b, c, and d corresponding to the signal locations a, b, c, and d, respectively, in the track and signal layout shown in Fig. 1). Points 11, b, c, and d designate entrance or eXit ends of routes, extending over a crossover having switches A1 and B1, between locations at and b, c and b, or c and d in either direction. Light indication devices AKE, BKE, CKE, and DKE are located in the track model adjacent the push button circuit controllers APB, BPB, CPB, and DPB, respectively. The indication devices are preferably capable of being illuminated with either of two different colors, such as yellow and blue.

Each of the push button circuit controllers is of the self-restoring type, and is provided with normally closed and normally open contacts. Fig. la shows how these contacts are included in the energizing circuits of push button repeater relays APBR, BPBR, CPBR, and DPBR to insure that the push buttons are electrically interlocked so that only one of the push button repeater relays can be energized at one time. Thus, if push button BPB is operated, its normally open contacts 2 and 3 are closed to complete the energizing circuit of its repeater relay BPBR, and its normally closed contact 1 is opened to break the feed to the energizing circuits of all the other push button repeater relays. The energizing circuit for relay BPBR may be traced from positive battery, indicated by the letter B, contact 1 of push button APB, con tact 2 of push button BPB, normally closed contacts 4 of push buttons CPB and DPB, normally open contact 3 of push button BPB, and operating winding of relay BPBR to negative battery indicated by the letter N. Relay BPBR remains energized until push button BPB is released to open its contacts 2 and 3.

As shown in the drawings, each of the push button circuit controllers APB, BPB, CPB, and DPB is of the pushpull type such, for example, as shown in Letters Patent of the United States No. 2,295,301, granted September 8, 1942, to W. E. Smith, for Circuit Controllers. Each of these circuit controllers has normally open and normally closed contacts. Contacts 1 and 4 of circuit controller CPB, for example, are normally closed, and become opened when the push button for this controller is pushed in, but which remain closed when the controller button Contact 5 of circuit controller CPB, on the other hand, is normally closed, and remains closed when the controller button is pushed in, but becomes opened when the button is pulled out. Contacts .2 and 3 of circuit controller CPB are normally open, and become closed when the controller button is pushed in, but remain open when the controller button is pulled out.

Referring now to Fig. 1d, this figure shows the set-up relays ASR, BSR, CSR, and DSR, of which there is one associated with each push button. The energizing circuit of each set-up relay comprises, in series, a back confact I of the conditioning relay2CR,.a front contactl of gized, and its associated'destination relay isalso deenergized.

The holding circuit of each set-up relay includes, in series, its own front contactl, a back contact of a destination relay repeater DRP, and a normally closed contact of a cancel push button. The contact of relay DRP in this circuit is bridged by a front contact of each destination relay associated with the exit end of allpossible routes emanating from the entrance which has been selected.

For example, the holding circuitfor relay BSR includes back contact 2 -of relay DRP which is connected in parallel with front contact 2 of relays ADR and CDR which are destination relays associated'with a and c which are the possibleexits for routes emanating from b.

The energization of any one of the set-up relays completes an energizing circuit for the conditioning relay CR over one of the simple circuits shown in Fig. 1d, each of which may be traced from terminal N through the winding of relay CR and front contact'2 of the selected set up relay to terminal B. Another energizing circuit for relay CR, which will be discussed hereinafter, includes front contact 5 of relay DRP. The energization of conditioning relay CR has two main effects. At its back contact 1, it breaks the battery feed to the energizing circuits of all the set-up relays, and at its front contact 2, it applies the battery feed to the energizing circuits of all the destination relays ADR, 'BDR, CDR, and DDR. This assures that the next push buttonwhich is operated will energize one of these destination relays instead of a set-up relay. Theenergizing circuit for each destination relay .includes, in series, afront contact of its assoicated push button repeater relay and a back contact of the associated set-up relay. For example, relay ADR is energized by a circuit traced from terminal'B over front contact 2 of relay CR, front contact 2 of relay APBR, back contact 3 of relay A511, and the winding of relay ADR to terminal N. The energization of any one of the destination relays completes the simple energizing circuit for the destination repeater relay DRP shown in Fig. 1d, the purpose of which is explained later. The energizing circuit for relay DRP may be traced from battery terminal N through the winding of relay DRP and, in multiple; front contacts 3 of relays ADR and DDR and front contacts 4 of relays BDR and CDR to battery terminal B.

The route relays 'employedwith this systemare preferably of the well-known polar stick relay typenwhich, when deenergized, remain in' the position to which' they were last operated. Each is. provided with a reverse coil It is, however, to be understood thattwoseparate relays may, if desired, be used instead of .a single polar relay, one of which carries out the functions of thepolar relay energized normaLand the other of which carries outathe functions of the polar relay energized reverse. Suitable interlocking would, of course, have .to be. provided, in order to prevent both relays being picked up together.

The operating circuits for' the route" relays are shown coil comprises, in series, a front contact of the destination relay associated with the route exit, a front contact .of the set-up relay associated with the route entrance, and

a number ofcontacts of the other route relays to provide the necessary interlocking between route relays for conflicting routes, and any other interlocking that may be required, in well-known manner. The circuit for the (N) coil of each relay includes a front contact of the associated approach lock relay and a back contact of a normalizing relay. For example, the circuit for normal winding (N) of relay ABLR passes from terminal B .at front contact 1 ofrelay ABLS in Fig. 10, through winding (N) of relay ABLR, andback contact 2 of relay ANR to terminal N. The energizing circuit for'winding (R) of relay ABLR extends from terminal N, at the bottom of Fig. 14, through front contact 5 of relay BDR, from contact 4 of relay ASR, winding (R), normal contact 2 :of relay BALR, normal contact 2 of relay ,CBLR and normal contact 2 of relay.BCLR to terminal B. Similar circuits may be traced for the other route relays.

The indication devices AKE,BKE, CKE, DKE, in the track model in Fig. la provide visual indication of the routes set up and may be lamp caps or lenses backed by electric lamps which are controlled by the circuits shown in Figs. lb and 1d. Each comprises a lamp, for example, -A(H)KE, shown in Fig. lb, which, when energized, causesa yellow indication light to be displayed, and a second lamp, for example A(B)KE, which, when energized, causes a blue indication light to be displayed. These indicationlights are preferably so arranged that the two colorsare displayed alternatively through the same single aperture in the lamp cap or lens. This may, for example, be done by using a light unit suchas is described in the complete specificationof British Patent No. 649,063, in the names of Westinghouse Brake and Signal Company, Limited, and others.

The control of these indication lamps is such that a yellow aspect is displayed for routes to be traversed from left to right, as viewed in Figs. 1a and 1 while a blue aspect is displayed for routes to be traversed from right to left. These lights are for the purpose of indicating to the operator when the operation of a push button has had the "desired effect. Thus, to set up a route from c to d, push button CPB is operated'first, and this esults in a flashing yellow lighten the control panel at CKE to indicate that the correct set-up relay is energized and conditions are now correct for the setting up of the route to be completed by the operation of the button at the exit end of the desired route, in this case, push button DPB. When the route relay is energized in response to the subsequent operation of this push button, the flashing light at CKE becomes steady, and another steady yellow light is displayed at the exit end of the route at DKE. Had the route been set up for movement in the opposite direction, i. e. from right to left as viewed in Figs. 1a and 1 then the lights would have been blue, instead of yellow, and that shown at DKE wouldhave flashed at first, instead of that at CKE.

Referring to .the circuits shown in Figs. lb and 1d, by means of which these indication lights are controlled, it will be seen that the lamps (H)KE and (B)KE, giving. the yellow and blue indications, respectively, are supplied alternately from a flashing alternating current supply, or from a steady alternating current supply. The flashing may be.produced in any suitable manner by a mechanical or an electrical oscillator, such, for example,as the flasher relay Flbshown in Fig. 1d. The selection of the lamps to be energizedis carried out by contacts operated by the route relays, and it will. be seen that, as it is only the indication at the entrance'end of a route that flashes, it is necessary to provide a flashing'supply only for yellow lamps A(H) KE and C(H)KE and for blue lamps B(B)'KE and D'(ZB)'KE.

The circuit-by-which flashing light O(H)KE is lit is as Thecircuit for each reverse .4 follows: from terminal NX through the filament of lamp C(H)KE, normal contact 4 of relay CDLR, normal contact 4 of relay CBLR, front contact 8 of relay CSR and contact 1 of flasher relay F R to terminal BX. Steady lighting of lamp C(H)KE is accomplished through a circuit from terminal NX, through the filament of lamp C(H)KE and reverse contact 5 of relay CBLR or of relay CDLR to terminal BX. Similar circuits may be traced for the other lamps.

Referring now to Fig. is, each of the approach locking relays ABLS, BALS, CDLS, and DCLS is normally energize by both a pickup and a stick circuit, while a signal for governing trafiic movements over a corresponding route is controlled to indicate stop, and an approach section in the rear of the corresponding signal is unoccupied. The pickup circuit for relay BALS, for example, passes from terminal B, through contact 2 of relay BHR, contacts 4 of relays WTR and XT R, contact 4 of relay llWLR in multiple with contact 4 of relay YTR, contact 4 of relay ZTR, contact 4 of relay VTR, and the winding of relay BALS to terminal N. The stick circuit for relay BALS passes from terminal B, through contact 2 of relay BHR, contact 2 of relay BALS, and the winding of relay BALS to terminal N. A time element device, which may be a time element relay, designated by the reference character TH with a prefix corresponding to the location of the associated signal, and a timing stick relay, designated by the reference character IS with a corresponding prefix, are associated with each approach locking relay for at times effecting delayed operation of the corresponding approach locking relay. Each of the time element relays is of a type having a front contact which becomes closed only when the relay by which it is operated has been energized a measured period of time. Each of the timing stick relays is of a slow release type having a back contact which becomesclosed only upon the lapse of a brief period of time after the relay by which it is operated has become deenergized.

Each of the track stick relays is normally energized by both a pickup and a stick circuit, and becomes deenergized when a train enters a corresponding track section. The pickup circuit for relay WTS, for example, passes from terminal B, through contact 5 of relay WTR (Fig. 12), contacts 3 of relay BALR and BCLR, and the winding of relay WTS to terminal N. The stick circuit for relay WTS passes from terminal B, through contact 5 of relay WTR, contact 1 of relay WT S, and the winding of relay WTS to terminal N.

In the track and signal layout diagram, shown in Fig. 1), each track, comprising two parallel series of track rails, is represented by a double line, in order to simplify the drawings. The tracks are divided by insulated joints, designated by the reference character 0, into route sections, designated by the reference character 0, into route sections, designated by the reference characters WT, XT, ZT, YT, and UT, and approach sections, designated by vthe reference characters RT, ST, TT, and VT.

Each of the track sections is provided with a track circuit, including a suitable source of current, such as a battery, designated by the reference character y, connected across the rails adjacent one end of the section, and a track relay, designated by the reference character R preceded by the reference character for the corresponding section, connected across the rails adjacent the opposite end of the section. In order to simplify the drawings, the track batteries y for the approach sections are not shown.

Signals SA, SB, SC, and SD are placed adjacent the locations a, b, c, and d, respectively, signals SA and SC governing traflic movements toward the right, as shown in the drawings, which we shall assume is the eastbound direction, and signals SB and SD governing traffic movements in the opposite or westbound direction. The signals may be of any suitable design such, for example, as the well-known Searchlight type.

The operation of the apparatus thus far described is as follows: Assuming that it is desired to set up a route from b to c, push button BPB is first pushed in to close its normally open contacts 2 and 3, and to open its normally closed contacts 1 and 4. Push button repeater relay BPBR is accordingly energized over a previously traced circuit shown in Fig. 1a.

The picking up of relay BPBR completes the energizing circuit for set-up relay BSR extending, see Fig. 1d, from positive battery B, over contact 1 of the conditioning relay CR, contact 1 of the push button repeater relay BPBR, contact 1 of the destination relay BDR, and the energizing winding of relay BSR to negative battery at N. 'Relay BSR closes its contact 1 to complete a holding circuit for itself extending from positive battery B, over contact 1 of a cancel push button, back contact 2 of relay DRP, contact 1 of relay BSR, operating winding of relay BSR, to negative battery N.

At its front contact 8, Fig. 1d, relay BSR also completes a circuit for the flashing of the blue indication lamp B(B)KE from terminal BX, through contact 1 of relay FR, contact 8 of relay BSR, normal contacts 4 of relays BALR and BCLR, respectively, and lamp B(B)KE to terminal NX. The normal contacts of route relays BALR and BCLR in this circuit are to remove the flashing source of energy after the desired route has been established from point b. Had there been other possible routes having point b as their point of entrance, then similar normal contacts of the route relays of those routes would also have been included in the circuit for the flashing blue light B(B)KE.

The operator now releases push button BPB, which, being of the self-restoring type, opens its contacts 2 and 3, and relay BPBR releases, opening, at its contact 1, the previously described energizing circuit for relay BSR, which relay, however, is held energized over the holding circuit traced above.

The energization of set-up relay BSR completes, at its contact 2, Fig. 1d, the energizing circuit for the conditioning relay CR, as described above, and also, at its contacts 5 and 6, prepares the route relays of all routes having point b as their entrance end for reversal when the appropriate destination relay is subsequently energized. Thus, contact 5 of relay BSR is included in the energizing circuit for the reverse coil of route relay BALR for route ba, and contact 6 of relay BSR is included in the energizing circuit for the reverse coil of route relay BCLR for route bc. Should it, at this stage, be desired to cancel the steps taken to set up a route before the operation of the push button at the route exit, due to a change of plan, or a mistake, for example, the operator operates the: cancel push button indicated in Fig. la, which operation opens its normally closed contact 1, thus breaking the holding circuits for all the set-up relays, and relay BSR accordingly releases, followed by relay CR (Fig. 1d) whose energizing circuit becomes broken at contact 2 of relay BSR.

When the conditioning relay CR picks up, it opens its contact 1, thus removing the battery from the energizing circuits of all the set-up relays, and closes its contact 2, transferring the battery feed to the energizing circuits of all the destination relays. In this manner, all other buttons are automatically rendered exit buttons and the next one to be operated, instead of resulting in the energize.- tion of its associated set-up relay, causes the energization of a destination relay. Thus the operation of push button CPB energizes its relay CPBR, Fig. 1a, which at its contact 2, completes the energizing circuit of destination relay CDR.

Upon picking up, relay CDR completes, at its contact 4, the energizing circuit of destination repeater relay DRP which picks up, opening its contact 2. This breaks the previously traced holding circuit for set-up relay BSR, Fig. 1d. The holding circuit for relay BSR however, is maintained intact by contact 2 of relay CDR, connected in'parallel with contactLZ-of .relayDRP, and which was closed when destination relay CDR picked up. At its contact 5, destinationrelay CDRcompletes the energizing circuit for the reverse coil (R) of the route relay BCLR for the route b-c, provided that the'interlocking permits this to be done. T hecircuit for the reverse coil (R) of route relay BCLR passes from terminal B, through contactsS of relays ABLR, CDLR, BALR, and DCLR, contact 8 of relay CBLR, winding (R) of relay BCLR, contact 6 of relay BSR, and contact 5 of relay CDR to terminal N.

Route relay BCLR thenreverses, and effects energization of winding (R) of relay 1WLR'by a circuit passing from terminal B, at thetmiddle'right of Fig. 1e, through contacts 2 of relays XTR and YTR, contacts 7 of relays ABLR, CDLR, BALR, DCLR, and BCLR, contact 1 of emergency-switch control lever 1V, and winding (R) of relay IWLR to terminal N. Relay IWLR will then reverse its contacts, thereby completing operating circuits for switch mechanisms AIM and BlM, passing from terminal B, through contact 2'of relay IWLR, mechanisms AIM and BlM in multiple, and contact 3 of relay IWLR to terminal N.

Relay BNR previously became energized by its pickup circuit passing from terminal B, through contact 5 of circuit controller BPB, contact 7 of relay BSR, and the winding of relay BNR to terminal N. Relay BNR is then retained energized bya stick circuit which is the same as the pickup circuit just traced execept that it includes contacts 1 of relays WTR and BNR'instead of contact 7 of relay BSR.

With windings (R) of relays BCLR and 1WLR energized, and the contacts of these relays therefore moved to the reverse position, relay BHR now becomes energized by a circuit passing from the terminal B, in the upper left of Fig. 112, through contacts 3 of relays WTR and XTR, contact 9 of relay BCLR, contact 1 of relay IWLR closed in the reverse position, contacts 3 of relays STR and YTR, contact 3 of relay BNR, and the winding of relay BHR to terminal N. With relay BHR energized, mechanism BHG of signal SB becomes operated by a circuit passing from terminal B, through contact 1 of relay BHR, and mechanism BHG to terminal N.

Mechanism BHG then operates signal SB for displaying a proceed indication for governing a westbound traffic movement by the route bc over switches A1 and B1 in the reverse position.

Route relay BCLR, reversing, also opens'its contact 4 and closes its contacts 5 and 6, replacing the flashing supply to'indication lamp B(B)KE by the steady supply, and also connecting the steady supply to indication lamp C(B)KE, so that indication deviceBKE ceases'to flash and, together with indication device C'K'E, becomes steadily illuminated, indicating to the operator that the route b-c has been set.

The operator then releases push huttonCPB, and relay CPBR accordingly releases, opening its contact 2, so that destination relay CDR also releases, *RlayCDR releasing, opens its contact2 inthe previously traced holding circuit for set-up relayBSR (-Fig. 1d), and'opens its contact 4 in the 'energizingcircuitof relay DRP, which is provided with slow release characteristics. Boththese relays thus release;re lay"DRP only-at the end-of its time delay to=insurethat relay BSRhas time to' open its contact 1 in its holding circuit before relay DRP recloses its contact 2. "The release of relay -BSR opens one energizing circuit of conditioningrelay-CR at contact 2 of relay "BSR, and the -=release 'of relay DR-P to open its contactS opens 'the-second=ene rg'izing circuit so that relay CR releases.

Thereversal of a route relay,-besides causing the steady energization of the selected in'dication lights AKE, BKE, CKE, and DKE, mayalso causethe illumination of other lamps (not .shown)'mounted along the representa- 'tion'of the track onthe track diagram, in such a way as to indicate'to theoperator the'routefisetiup. .This can be accomplished, for. example, 'b'y'the methods .disclosed in British patent specificatiouNo. 518,422.

The route relay 'BCLR may be returned to normal, thus releasing the'route set-up, either manually, or automatically by the passage of the train or vehicle. vAssociated with each route entrance is a normalizing relay, that associated Withpointb, relay BNR, being illustrated in Fig. 1e. The pickup and stick circuits for relay BNR have already been traced. It will be noted that as soon as relay BSR picks up at the commencement of a route-setting operation, its contact 7 is closed, and completes the pickup circuit for relay BNR which thentpicks up and completes, at its contact 1, a holding circuit for itself, so that it remains energized after the set-up relay releases when the route is setup. Since the holding cir cuit includes contact 1 of relay WTR,"relay BNR will become deenergized when a'train enters the corresponding track section WT. The circuits for relays ANR, CNR, and DNR are similar to the circuits already traced and described for relay 'BNR. ContactS of circuit controller BPB is a contact which is closed when the push button BPB is in its normal position, and also when it is pressed for the purpose of setting a'route, as described above, but which is broken when'the push button is pulled instead ofpressed. It will be seen that relay BNRwill be released automatically when a train enters section WT, or it may be released manually if contact 5 of circuit controller BPB is'openediby pulling the button of circuit controller BPB.

The energizing circuit'forthe normal coil (N) of the route relay BCLR, in multiple with that of route relays of all other routes originating'at point 12, in this case,

relay BALR, includes a back contact 2 of relay 'BNR, and contact 1 of approach locking relay'BALS.

-lt will'thus be seen that. as soon as a setup relay is picked up by the operation of a push button at a point corresponding to the entrance of a route, the normalizing relay associated'with that entrance becomes energized, and remains so until either the associated push button is pulled or contact 1 of the associated track relay opens as the train enters the corresponding entrance track circuit. When either of the contacts I1 of relay WTR or 5 of circuit controller BPB is opened, normalizing relay BNR releases and, closing its contact 2, completes the energizing circuit for normal winding'N of relay BCLR, if relayBALS is energized so that its contact 1 is closed. It will be appreciatedthat, if desired, the automatic cancellation feature may be dispensed with by the simple expedient of removing contact .1 of relay WTR from the holding circuit of relay BNR; the route-will then remain set up until manually cancelled by the pulling-of the push button. Also, ifipre'ferre'd, in order to guard against accidental cancellation of a route on account of a broken wire, for example, the normalizing relay ircuit may be modified so that the normalizing relay has to be energized to establish a routeto normal and the front contact of the normalizing relay-is then included in the energizing circuit of the route relay (N) coil in place of the back contact 2 of the normalizing relay.

When relay BHR becomes energized for clearing signal SB, its contact Z'Will open the circuits previously traced for relay BALS, causingrelay BALS to become .deenergized. If a leverman then decides to stop an approaching Westbound train at signal SB, he will pull out the operating button of circuit controller BPB to open its contact 5 and therebyideenergize relayBNR. When relay BNR becomes deenergized, its contact 3 will open the circuit for relayBHR, causing *relay BHR to also be deenergized. If the train has not yetentered approach section VT, relay BALS will now become energized by a pickup circuit'which is thesame'as the pickup circuit previously-traced .for this relay except that contact'4 of relay IWLR is open, .and..contact 50f relay IWLR is closed in multiple with contact 4 of relay ZTR. Relay 11 BALS, upon becoming energized, completes its stick circuit previously traced.

If the train has entered section VT before the levernian pulls circuit controller BPB out to deenergize relay BNR, the second pickup circuit just described for relay BALS will be open at contact 4 of relay VTR, and therefore relay BALS cannot become energized at once. Time element relay BTH will, however, become energized by a circuit passing from terminal B, through contact 2 of relay BHR, contacts 4 of relays WTR, XTR, and YT? contact of relay IWLR in multiple with contact t of relay ZTR, contact 4 of relay BNR, back point of contact 1 of relay BJS, winding of relay BTH, and contact 3 of relay BALS to terminal N. Upon the lapse of a measured period of time, relay BTH will close its contact 1 at the front point, thereby completing a pickup circuit for relay BIS which is the same as the energizing circuit traced for relay BTH, except that it includes the front point of contact 1 of relay BTH instead of the back point of contact 1 of relay BIS. Relay BIS, upon becoming energized, will complete its stick circuit, which is the same as its pickup circuit just traced, except that it includes the front point of contact 1 of relay BIS instead of the front point of contact 1 of relay BTH. Relay BIS, upon becoming energized, opens its contact 1 at the back point, thereby deenergizing time element relay BTH. As soon as contact 1 of relay BTH becomes closed at its back point, a third pickup circuit will be completed for relay BALS, which is the same as the second pickup circuit described for this relay as far as contact of relay ZTR in multiple with contact 5 of relay 1WLR, and which then passes through contact 4 of relay BNR, front point of contact 1 of relay BIS, back point of contact 1 of relay BTH, and the winding of relay BALS to terminal N.

If, however, the leverman does not attempt to stop the train before it passes signal SB, relay BHR will become deenergized by the opening of contact 3 of relay WTR when the train enters section WT, and relay BNR will become deenergized by the opening of its holding circuit by contact 1 of relay WTR. Relay WTS will also become deenergized by the opening of contact 5 relay WTR. Relay WTS will then remain deenergized as long as contact 3 of relay BCLR remains open. When the train has passed over all the route track sections WT,

Xi, and YT, in the route from b to c, relay BNR will still remain deenergized because contact 7 of relay BSR 18 open. Relay BALS will now, however, become energized by a fourth pickup circuit, which is the same as the second pickup circuit traced for this relay except that it includes contact 2 of relay WTS in multiple with contact 4 of relay VTR, if approach section VT is unoccupied, but which, if approach section VT is occupied, will pass through contact 2 of relay WTS Without contact 4 of relay VTR. With relay BALS again energized I and relay BNR deenergized, windings (N) of relays BCLR and BALR will now be energized by the circuit passing from terminal B, through contact 1 of relay BALS, windings (N) of relays BCLR and BALR, and contact 2 of relay BNR to terminal N. The contacts of relay BCLR will thus be returned to their normal nositlon Relay WTS will then again become energized by its circuit previously traced.

Should an attempt be made to set up a route which is in conflict with a route already set up, a flashing indication will be obtained, in the manner described, when the entrance button is pressed, but, when the exit button is pressed, no steady indication will appear, and the flashing indication will be extinguished when the exit button is released. Suppose, for example, that, having set up the route bc as described above, the operator tries to set up the route a--b. On button APB being pressed, relay APBR is energized and picks up, closing its front contact 1 in the energizing circuit of set-up relay ASR (Fig. 1d).

Relay ASR accordingly picks up and, at its front contact 1, completes a holding circuit for itself including contact 1 of relay DRP in parallel with contact 2 of relay BDR. At its front contact 5, relay ASR than completes a circuit for the yellow lamp A(H)KE from the flashing alternating current supply, so that a flashing indication is given at point a of the track diagram. When push button BPB is now pressed, relay BPBR picks up and, at its front contact 2, completes the energizing circuit for destination relay BDR. Relay BDR picks up, and closes its front contact 5 in the energizing circuit of route relay ABLR reverse coil (R) (Fig. 11)) but, although front contact 4 of relay ASR in this circuit is also closed, the circuit will be held open at one or more of the interlocking contacts which include a normal contact 2 of route relay BCLR which is reversed at this time. Route relay ABLR accordingly remains normal, and does not close its reverse contact 5, and lamp A(H)KE accordingly continues to flash. When the push. button BPB is released, releasing relay BPBR, the energizing circuit of destination relay BDR is opened at contact 2 of relay BPBR, and relay BDR releases, opening its contacts 2 and 4, the former breaking the holding circuit for relay ASR and the latter that for relay DRP. Set-up relay ASR accordingly releases, followed by relay DRP, at the end of its time delay, and relay CR.

it is to be noted that, instead of providing the contacts on the push buttons'as illustrated in Fig. In for the purpose of interlocking so that only one push button can effectively be operated at one time, additional contacts may alternatively be provided on the push button repeater relays, PBR, thus simplifying the design of the push buttons. In either case, it is impossible for the energization of two route relays to be initiated simultaneously.

It may also be pointed out that the circuits shown insure that no detrimental effect results if, by mischance, a push button is operated which is associated with a point which cannot be the exit point of a route emanating from the point previously identified as an entrance. Thus, if it is desired to set up a route from a to 1'2, and the operator operates push button APB identifying point a as an entrance point, set-up relay ASR and conditioning relay CR will both become energized as previously described. lf, now, the operator, by mistake, operates push button DPB at point d, which cannot be the exit point of any route emanating from point a, destination relay DDR and repeater DRP will both become energized, and the latter will break the holding circuit for ASR at its contact 1, so that relay ASR becomes deenergized. Relay CR, however, is maintained energized by contact 5 of relay DRP, so that contact 1 of relay CR remains open and prevents the wrongly operated push button from energizing set-up relay DSR and thus initiating the setting up of a route not required. When push button DPB is released, relay DPBR releases, and opens its contact 2, thus deenergizing relay DDR which, in turn, opens its contact 3, so that relay DRP also releases. The apparatus thus automatically resumes its normal position, and push button APB may again be operated to identify point a as an entrance point. For the above feature to function correctly, it is necessary, when the wrong exit push button is operated, for contact 5 of relay DRP to close before contact 2 of relay ASR opens, otherwise the conditioning relay CR will become deenergized and the crroneously operated push button become identified as a route entrance. As contact 2 of relay ASR opens in response to the opening of the holding circuit of relay ASR at contact 1 of relay DRP, it is necessary, in order to obtain the above feature, that contacts 1 and 5 of relay DRP be adjusted so that, when relay DRP picks up, contact 5 closes before contact 1 opens. Alternatively, contact 5 of relay DRP may be replaced by a front contact of each of the destination relays, all connected in-parallel, so that, as soon as one of these relays picks up, the energizing circuit of relay CR is maintained. S1nce,'in the above action, the holding circuit for the set-up relay ASR is broken only when repeater relay DRP picks up, relay ASR cannot drop away and open its contact 2 until after relay DDR will have closed its abovementioned additional front contact.

The operation of the apparatus has been described for a few typical conditions. It is believed that, in view of the foregoing description, the operation of the apparatus for'any other possible condition can be readily traced from the accompanying drawings.

Although we have herein shown and described only one form of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our in- 'vention.

Having thus described our invention, what we claim is:

1. In a railway traffic control system for a stretch of track comprising a plurality of routes established in response'to the sequential operation of circuit controllers associated with the entrance and exit ends of the routes, therebeing only one such controller at each end of all possible routes, the combination comprising, a set-up relay and a destination relay associated with each of said circuit controllers, a conditioning relay and a release relay common to all of said circuit controllers, an energizing circuit for each set-up relay controlled by the associated circuit controller and including a back contact of said conditioning relay and a back contact of the corresponding destination relay, a stick circuit'for each set-up relay to hold a selected relay energized after the associated circuit controller is deactivated and while another'circuit controller is being operated to select a destination relay, each said stick circuit including in multiple a back contact of said release relay and a front contact of the destination relay associated with the exit end of eachpossible route initiated by the selected setup relay, an energizing circuit for each destination relay circuit for said conditioning relay completed whenany :one of said set-up relays is energized, an energizing circuit for said release relay completed when any one of said destination relays is energized, a route relay of the polar stick type for each possible route through said stretch, each route relay being operable to a reverse position to establish the corresponding route and occupying a normal position when said corresponding route is not established, circuit means effective to operate a selected route relay to its reverse position when the setup and destination relays associated with the entrance and exit ends respectively of the selected route are energized, said circuit means including normal contacts of non-selected route relays corresponding to conflicting routes, said selected route relay holding in said reverse position because of its stick characteristics when said associated set-up and destination relays release upon the deactivation of the circuit controller associated with the exit end of the selected route, and other circuit means responsive to the passage of a train over said selected route or to a manual restoring action to operate said selected route relay to its normal position to cancel said selected route.

2. In a railway trafiic control system for a stretch of track comprising a plurality of routes established in response to the sequential operation of circuit controllers associated with the entrance and exit ends of the routes, there being only one such controller at each end of all possible routes, the combination comprising; a set-up relay, a destination relay, and a normalizing relay associated with each of said circuit controllers; a condition- *l l ing-relay and a release relay common to all of said circuit controllers, an energizing circuit for each set-up relay controlled ,by the associated circuit controller and including a back contact of said conditioning relay and a back contact of the corresponding destination relay, astick circuitfor each set-up relay to hold a selected relay energized after the associated circuit controller is deactivated and while another circuit controller is being'operated to select a destination relay, each said stick circuit including in multiple a backcontact of said release relay and a front contact of the destinationrelay associated with the exit end or each possible route initiated by the'selected set-up relay, an energizing circuit foreach destination relay controlled by the associated circuit controllerand including a back contact of the corresponding set-up relay and a front contact of said conditioning relay, an energizing circuit for each normalizing relay includinga normally closed contact of the associated circuit 'controller and a front contact of the corresponding set-up relay, a stick circuit'foreach normalizing relay including said associated normally closed controller contact and another normally closed contact opened in response to a train entering the'route whose'entrance end corresponds to said associated circuit controller, an energizing circuit for said conditioning relay completedwhen-any one of said'set-up relays is energized,an energizing circuit for said release relay completed when any one of said destination relays is energized, a route relay of the polar stick type foreach possible route through said stretch, each route relaybeing operable to a reverse position to establish the corresponding routeand occupying a normal position when said corresponding route'is not established, circuit means effective to operate a selected route relay to itsreverse position when the set-up and destination relays associated with'the entrance and exit ends respectively of the selected route are energized, said circuit means including normal contacts of nonselectedrouterelays corresponding to conflicting routes, said selected route relay holding in-said :reverse position because of its stick charaeteristics when said associated set-upand destination relays release uponthe deactivation ofthe circuit controller-associated with'exit end of the selected route, and othercircuit meansincluding :a back contact of the'normalizing relay associated with the entrance end of said selected route to .operatesaidselected route relay to'its normal position to. cancel said selected route.

3. In a railway traffic control system for a stretch of track comprising a plurality of routes etablished in response to the sequential operation of circuit controllers associated with the entrance and exit ends of the routes, there being only one such controller at each end of all possible routes, the combination comprising, a set-up relay and a destination relay associated with each of said circuit controllers, a conditioning relay and a release relay common to all of said circuit controllers, an energizing circuit for each set-up relay controlled by the associated circuit controller and including a back contact of said conditioning relay and a back contact of the corresponding destination relay, a stick circuit for each set-up relay to hold a selected relay energized after the associated circuit controller is deactivated and while another circuit controller is being operated to select a destination relay, each said stick circuit including in multiple a back contact of said release relay and a front contact of the destination relay associated with the exit end of each possible route initiated by the selected set-up relay, an energizing circuit for each destination relay controlled by the associated circuit controller and including a back contact of the corresponding set-up relay and a front contact of said conditioning relay, an energizing circuit for said conditioning relay completed when any one of said set-up relays is energized, an energizing circuit for said release relay completed when any one of said destination relays is energized, a route relay of the polar stick type for each 15 possible route through said stretch, each route relay being operable to a reverse position to establish the corresponding route and occupying a normal position when said corresponding route is not established, circuit means effective to operate a selected route relay to its reverse position when the set-up and destination relays associated with the entrance and exit ends respectively of the selected route are energized, said circuit means including normal contacts of non-selected route relays corresponding to conflicting routes, said selected route relay holding in said reverse position because of its stick characteristics when said associated set-up and destination relays release upon the deactivation of the circuit controller associated with the exit end of the selected route, other circuit means responsive to the passage of a train over said selected route or to a manual restoring action to operate said selected route relay to its normal position to cancel said selected route, and visual indication means associated with each of said circuit controllers, each indication means being controlled over reverse position contacts of said route relays to provide an indication of one color if the associated circuit controller represents the entrance end of the selected route and an indication of a different color if the associated circuit controller represents the exit end of the selected route.

4. In a railway trafiic control system for a stretch of track comprising a plurality of routes established in response to the sequential operation of circuit controllers associated with the entrance and exit ends of the routes, there being only one such controller at each end of all possible routes, the combination comprising; a set-up relay, a destination relay, and a normalizing relay associated with each of said circuit controllers; a conditioning relay and a release relay common to all of said circuit controllers, an energizing circuit for each set-up relay controlled by the associated circuit controller and including a back contact of said conditioning relay and a back contact of the corresponding destination relay, a stick circuit for each set-up relay to hold a selected relay energized after the associated circuit controller is deactivated and while another circuit controller is being operated to select a destination relay, each said stick circuit including in multiple, a back contact of said release relay and a front contact of the destination relay associated with the exit end of each possible route initiated by the selected set-up relay, an energizing circuit for each destination relay controlled by the associated circuit controller and including a back contact of the corresponding set-up relay and a front contact of said conditioning relay, an energizing circuit for each normalizing relay including a normally closed contact of the associated circuit controller and a front contact of the corresponding set-up relay, a stick circuit for each normalizing relay including said associated normally closed controller contact and another normally closed contact opened in response to a train entering the route whose entrance end corresponds to said associated circuit controller, an energizing circuit for said conditioning relay completed when any one of said set-up relays is energized, an energizing circuit for said release relay completed when any one of said destination relays is energized, a route relay ot' the polar stick type for each possible route through said stretch, each route relay being operable to a reverse position to establish the corresponding route and occupying a normal position when said corresponding route is not established, circuit means effective to operate a selected route relay to its reverse position when the set-up and destination relays associated with the entrance and exit ends respectively of the selected route are energized, said circuit means including normal contacts of non-selected route relays corresponding to conflicting routes, said selected route relay holding in said reverse position because of its stick characteristics when said associated set-up and destination relays release upon the deactivation of the circuit controller associated with the exit end of the selected route, a signal control circuit means effective to cause a signal at the entrance end of the selected route to display a proceed indication, said signal control means including a front contact of the normalizing relay associated with the entrance end of said selected route and a reverse contact of said selected route relay, and other circuit means including a back contact of said associated normalizing relay to operate said selected route relay to its normal position to cancel said selected route.

References Cited in the file of this patent UNITED STATES PATENTS 2,094,134 Obergfell Sept. 28, 1937 2,244,401 Pelican June 3, 1941 2,265,249 Preston Dec. 9, 1941 2,302,007 Coley Nov. 17, 1942 2,302,038 Langdon et a1 Nov. 17, 1942 2,317,472 Merkel Apr. 27, 1943 

